It isn't a vanilla weapon, however, the process just is exact or similar. I'm aware of adding magazines and simple scripting but I'm currently trying to figure out on how to add a different ammo type that isn't accepted by the weapon and have it load that type.
As I want to load these smokes
UGL_FlareWhite_F
UGL_FlareGreen_F
UGL_FlareRed_F
UGL_FlareYellow_F
UGL_FlareCIR_F
1Rnd_Smoke_Grenade_shell
1Rnd_SmokeRed_Grenade_shell
1Rnd_SmokeGreen_Grenade_shell
1Rnd_SmokeYellow_Grenade_shell
1Rnd_SmokePurple_Grenade_shell
1Rnd_SmokeBlue_Grenade_shell
1Rnd_SmokeOrange_Grenade_shell
3Rnd_HE_Grenade_shell
3Rnd_UGL_FlareWhite_F
3Rnd_UGL_FlareGreen_F
3Rnd_UGL_FlareRed_F
3Rnd_UGL_FlareYellow_F
3Rnd_UGL_FlareCIR_F
3Rnd_Smoke_Grenade_shell
3Rnd_SmokeRed_Grenade_shell
3Rnd_SmokeGreen_Grenade_shell
3Rnd_SmokeYellow_Grenade_shell
3Rnd_SmokePurple_Grenade_shell
3Rnd_SmokeBlue_Grenade_shell
3Rnd_SmokeOrange_Grenade_shell
As it is meant for it been have by an RTO [Radio Telephone Opeartor] to ease the gap between the RTO and the location he needs to pop smoke on.